Novel Nano Felodipine-Loaded Spanlastic Carriers for Buccal Delivery: Formulation, Optimization and Characterization

Felodipine, a Dihydropyridine calcium channel antagonist, is widely used to treat hypertension and angina pectoris. Its highly lipophilic nature and low aqueous solubility classify it as a Biopharmaceutics Classification System Class II Drug. When administered orally, Felodipine undergoes extensive first-pass hepatic metabolism, resulting in low oral bioavailability (15%) and posing challenges for effective antihypertensive therapy. This study aimed to formulate drug-loaded nanovesicular Spanlastics within oral fast-dissolving films, enabling buccal mucosa delivery to bypass hepatic metabolism and enhance drug bioavailability. Felodipine nanovesicular Spanlastics were formulated using a modified Ethanol Injection method. Design Expert® Software Version 13 and a 23 factorial design model determined the effect of formulation variables on response variables. The Spanlastics, characterized for particle size (ranging from 155.7 to 308.9 nm) and entrapment efficiencies (84.68 to 88.36%), showed lamellar, circularly shaped vesicles as observed through Optical and Transmission Electron Microscopy. These optimized Spanlastics were incorporated into oral fast-dissolving films, which exhibited substantial flexibility, sufficient mechanical strength, a disintegration time of 35 s, and rapid drug release of 95.99% within 5 min. Scanning Electron Microscopy imaging confirmed a smooth, porous, and uniform surface of the films. Short-term stability studies indicated that the films maintained stable physical and structural attributes. This research confirmed that Felodipine Spanlastic vesicles, due to their nanosize, enhance mucosal permeation and act as effective nanocarriers. Their incorporation into fast-dissolving oral films improves bioavailability through oro-mucosal tissue absorption for buccal delivery.